Glossary for Congenital metabolic disorders

17-20 desmolase deficiency: A form of congenital adrenal hyperplasia where a deficiency of 17-20-desmolase results males having ambiguous or female external genitalia due to impaired sex steroid production.

17-Beta-hydroxysteroid dehydrogenase III deficiency: A rare disorder characterized caused by an enzyme (17-ketosteroid reductase) defect only in the testes which results in a lack of testosterone which is needed during the fetal stage to give males there physical characteristics.

18-Hydroxylase deficiency: A rare genetic, metabolic defect where a deficiency of the enzyme 18-Hydroxylase which results in a reduced amount of aldosterone and salt wasting.

2-Hydroxyglutaricaciduria: A rare metabolic disorder characterized by high levels of a certain chemical (2-Hydroxyglutaric) which causes a serious progressive neurological disease and damage to the brain. The features of this disorder are variable and some cases are milder than others.

2-Methylbutyric Aciduria: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.

2-methylbutyryl-coenzyme A dehydrogenase deficiency: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.

3 alpha methylcrotonyl-Coa carboxylase 1 deficiency: A rare inherited disorder where lack of a certain enzyme (3-methylcrotonyl-Coa carboxylase) stops proteins with the amino acid leucine being metabolized normally by the body. The leucine builds up in the body and causes damage to the brain and nervous system. The severity of the condition is variable with some cases being mild enough to be asymptomatic. The condition differs from type 2 in that it originates as a defect in a different gene (MCC1 gene) but it causes the same enzyme deficiency.

3 alpha methylcrotonyl-coa carboxylase 2 deficiency: A rare inherited disorder where lack of a certain enzyme (3-methylcrotonyl-Coa carboxylase) stops proteins with the amino acid leucine being metabolized normally by the body. The leucine builds up in the body and causes damage to the brain and nervous system. The severity of the condition is variable with some cases being mild enough to be asymptomatic. The condition differs from type 1 in that it originates as a defect in a different gene (MCC2 gene) but it causes the same enzyme deficiency.

3-Beta-HSD, Deficiency of: A rare condition where the deficiency of a particular enzyme (3-Beta-Hydroxysteroid Dehydrogenase) results in reduced levels of adrenal hormones - mineralocorticoids, glucocorticoids and sex steroids. The condition results in variable degrees of salt wasting and abnormal sexual organ development depending on the level of deficiency.

3-Beta-Hydroxysteroid Dehydrogenase deficiency: A rare condition where the deficiency of a particular enzyme (3-Beta-Hydroxysteroid Dehydrogenase) results in reduced levels of adrenal hormones - mineralocorticoids, glucocorticoids and sex steroids. The condition results in variable degrees of salt wasting and abnormal sexual organ development depending on the level of deficiency.

3-Beta-Hydroxysteroid Dehydrogenase, Type II, Deficiency of: A rare condition where the deficiency of a particular enzyme (3-Beta-Hydroxysteroid Dehydrogenase) results in reduced levels of adrenal hormones - mineralocorticoids, glucocorticoids and sex steroids. The condition results in variable degrees of salt wasting and abnormal sexual organ development depending on the level of deficiency.

3-Hydroxyacyl-CoA Dehydrogenase II Deficiency: A rare genetic disorder involving the deficiency of an enzyme (hydroxyacyl-coa dehydrogenase). The severity of the symptoms is highly variable with some cases resulting in death during the first decade while others suffer psychomotor and regression. Symptoms tend to be more severe in males who suffer progressive neurodegeneration whereas females tend to suffer mainly from developmental delay.

3-alpha-Hydroxyacyl-CoA Dehydrogenase Deficiency: A rare inherited form of biochemical disorder characterized by the deficiency of a particular enzyme (3-Hydroxyacyl-CoA Dehydrogenase). The enzyme deficiency only affects certain body tissues, in particular the skeletal muscles. The lack of enzyme activity prevents some fats being converted into energy. Symptoms tend to be exacerbated during fasting as during fasting, the body tries to rely more heavily on fats for energy. Fatty acids that are not completely metabolized due to the enzyme deficiency may build up in various organs and cause serious complications.

3-alpha-hydroxyacyl-coenzyme A dehydrogenase deficiency: A rare inherited form of biochemical disorder characterized by the deficiency of a particular enzyme (3-Hydroxyacyl-CoA Dehydrogenase). The enzyme deficiency only affects certain body tissues, in particular the skeletal muscles. The lack of enzyme activity prevents some fats being converted into energy. Symptoms tend to be exacerbated during fasting as during fasting, the body tries to rely more heavily on fats for energy. Fatty acids that are not completely metabolized due to the enzyme deficiency may build up in various organs and cause serious complications.

3-methylcrotonyl-CoA carboxylase deficiency: A rare inherited disorder where lack of a certain enzyme (3-methylcrotonyl-Coa carboxylase) stops proteins with the amino acid leucine being metabolized normally by the body. The leucine builds up in the body and causes damage to the brain and nervous system. The severity of the condition is variable with some cases being mild enough to be asymptomatic.

3?-hydroxysteroid dehydrogenase deficiency: A ver rare form of congenital adrenal hyperplasia involving a deficiency of 3?-hydroxysteroid dehydrogenase which results in reduced production of adrenal steroids (mineralocorticoids, sex steroids and glucocorticoids). The disorder can occur in classical, non-salt wasting and late-onset varieties.

6-pyruvoyl-tetrahydropterin synthase deficiency: A rare genetic disorder where insufficient levels of tetrahydropterin leads to a build up of phenylalanine in the blood which can cause toxic side effects such as nerve damage or even brain damage. The condition does not usually cause any significant symptoms.

ACAD8 deficiency: An extremely rare metabolic disorder where the body is unable to metabolize certain proteins properly. More specifically, an insufficient level of the enzyme (isobutyryl-coenzyme A dehydrogenase) needed to metabolize the amino acid valine. The onset and severity of symptoms is variable.

ACAD9 deficiency: A metabolic disorder involving a deficiency of an enzyme (acyl-CoA dehydrogenase-9). The symptoms are variable and are usually triggered by a viral infection or ingestion of aspirin which can trigger a Reye-like episode which can cause death.

ACTH resistance: A rare inherited genetic disorder characterized by adrenal insufficiency due to the adrenal gland's inability to respond to ACTH and hence produce the hormone called cortisol.

Abetalipoproteinemia: A rare disorder involving abnormalities in fat metabolism. The resulting insufficiency of fats and vitamins affect the normal development and function of the body.

Acatalasemia: A rare inherited disorder involving a lack of erythrocyte catalase activity which affects lipid metabolism. The defect can manifest as one of two variants: Japanese variant (Takahara disease) or the Swiss variant which is asymptomatic.

Aceruloplasminemia: A rare, recessively inherited neurodegenerative disorder characterized by a lack of ceruloplasmin in the blood. The lack of ceruloplasmin results in abnormal iron use in the body and leads to iron deposits in various body tissues such as the brain, pancreas and liver. The iron overload results a neurodegeneration (ataxia, dementia and extrapyramidal disorders) and diabetes. Patients with only a partial absence of ceruloplasmin are often asymptomatic.

Acetyl-coa acetyltransferase 2 deficiency: A rare disorder where a genetic anomaly results in a deficiency of a particular enzyme (Acetyl-coa acetyltransferase 2) which is associated with mental retardation and reduced muscle tone. The enzyme is involved in lipid metabolism

Acid phosphatase deficiency: A group of inherited metabolic bone disorders varying in degree of severity and characterized a deficiency of alkaline phosphate which affects bone mineralization.

Acidemia, isovaleric: A rare genetic condition where the body can't process proteins adequately. More specifically, there are insufficient levels of the enzyme needed to break down an amino acid called leucine. This results in a build up of isovaleric acid which can harm the brain and nervous system. Some people suffer severe symptoms from birth and others suffer milder symptoms that come and go and are affected by such things as infections or consumption of high protein food.

Acidemia, methylmalonic: An inborn error of metabolism where amino acids in the body aren't metabolized properly resulting in high levels of the acid throughout the body.

Acidemia, propionic: An inherited genetic disorder where the body is incapable of processing some proteins and fats resulting in the accumulation of certain substances in the body which causes the symptoms of the condition. The condition can be life threatening.

Aconitase deficiency: A rare disorder where deficiency of an enzyme called aconitase results in muscle disease and intolerance to exercise.

Acute intermittent porphyria: A rare metabolic disorder characterized by a deficiency in the porphobilinogen deaminase enzyme which results in a build-up of porphyrins or its precursors in the body. Using certain drugs or eating certain foods can trigger the symptoms of the condition.

Acyl-CoA dehydrogenase, short chain, deficiency of: A rare disorder where the body lacks enzymes needed to convert some fats (short-chain fatty acids) into energy. Symptoms are exacerbated by fasting or acute illness. The severity of symptoms is variable with some patients remaining virtually asymptomatic their whole life while other suffer symptoms from infancy.

Acyl-CoA dehydrogenase, very long chain, deficiency of: A rare inherited genetic condition where the body is unable to convert certain fats to energy i.e. there is not enough of a certain enzyme which is needed to metabolize a type of fat called long-chain fatty acids. The build-up of these fatty acids in the body causes damage. There are three subtypes of the disorder each with varying severity: severe early-onset form, an intermediate form and an adult-onset form.

Adenosine deaminase deficiency: A rare disorder where a deficiency in the activity of adenosine deaminase causes severe immunodeficiency which in turn results in frequent severe bacterial, viral and fungal infections.

Adenosine monophosphate deaminase deficiency: A rare metabolic disorder characterized by a deficiency of adenosine monophosphate deaminase which affects muscle energy production. The condition is usually asymptomatic but some people suffer from muscle pain, cramps and fatigue following exercise.

Adenylosuccinate lyase deficiency: A rare inherited disorder characterized by a deficiency of the enzyme called adenlyosuccinate lyase which generally results in psychomotor retardation and autistic behavior.

Adrenal Hyperplasia, Congenital (General): Congenital adrenal hyperplasia is an inherited condition characterized by adrenal insufficiency. It is caused by a deficiency in an enzyme needed to produce certain adrenal hormones such as cortisol and aldosterone.

Adrenal hyperplasia, congenital, due to 11-Beta-hydroxylase deficiency: A rare form of congenital adrenal hyperplasia characterized by a deficiency of 11-Beta-hydroxylase which results in excess androgen production and hypertension. The disorder can occur in virilizing, hypertensive and salt-wasting forms and symptoms may range from mild to severe.

Adrenoleukodystrophy, autosomal, neonatal form: A rare inherited disorder involving the adrenal glands, testes and certain parts of the brain (white matter). It is a less severe form of leukodystrophy where an abnormality within the body cells prevents the metabolism of certain fats (long chain fatty acids).

Aldolase A deficiency: A rare condition where a deficiency of the enzyme called aldolase A causes muscle problems and anemia.

Alkaptonuria: A rare disorder where the abnormal accumulation of a particular acid (homogentisic acid) in the body causes connective tissue and bone damage. This damage gives tissues a dark or bluish discoloration.

Alpha-Mannosidosis: A rare condition which is characterized by a lysosomal storage defect.

Alpha-N-acetylgalactosaminidase deficiency, Type II: A very rare inherited metabolic disorder where deficiency of an enzyme (alpha-N-acetylgalactosaminidase) causes glycoplids to accumulate in body tissues and result in various symptoms. Type 2 occurs during the second or third decade of life and is milder than type I and doesn't involve neurological degeneration.

Alpha-ketoglutarate dehydrogenase deficiency: A metabolic disorder characterized by a deficiency of Alpha-ketoglutarate dehydrogenase which results in high levels of oxoglutaric acid in the urine as well as other severe symptoms.

Alpha-mannosidosis type II: A rare inherited metabolic disorder involving a deficiency of an enzyme (alpha-mannosidosase) which results in the accumulation of certain chemicals in the body which leads to progressive damage. This form of the condition is less severe than type I (infantile form).

Aminoacidopathies: Any of a group of inborn errors of metabolism which results in the build up in the body of one or more amino acids in the blood and/or urine. The range and severity of symptoms is hugely variable.

Aminoacylase 1 deficiency: A rare genetic disorder caused by an enzyme (aminoacylase-1) deficiency. There is still uncertainty whether the deficiency actually causes any of the symptoms observed in patients.

Anaemia, sideroblastic, X-linked -- ataxia: A very rare inherited disorder characterized by mild anemia and early onset neurological motor symptoms. The neurological symptoms tend to be relatively stable or slowly progressive with only occasional dependence on crutches or wheelchairs.

Andersen disease: An rare inborn error of metabolism involving glycogen storage and characterized by cirrhosis and sometimes liver failure. Lack of the amyl-transglucosidase enzyme and abnormal glycogen causes the condition.

Apolipoprotein C 2I deficiency: A rare inherited condition where a deficiency of apolipoprotein C-II impairs lipoprotein metabolism and results in a build up of chylomicrons and VLDL.

Apparent Mineralocorticoid Excess, type 2: A form of inherited high blood pressure that starts during early childhood. The condition is caused by a genetic defect which results in an inborn error of metabolism of peripheral cortisol. Type 2 causes similar symptoms to type 1 but the urinary steroid levels are different.

Apparent mineralocorticoid excess: A form of inherited high blood pressure that starts during early childhood. The condition results from a genetic defect which causes impaired metabolism of cortisol.

Arginase deficiency: A very rare urea cycle disorder caused by a deficiency of the enzyme (arginase) needed to convert ammonia to the urea which can then be removed in the urine. The condition leads to excess build-up of ammonia in the body which is toxic to the nervous system.

Argininosuccinase lyase deficiency, late onset: A rare inherited urea cycle disorder caused by lack of enzymes (argininosuccinase lyase) needed to turn ammonia into urea resulting in excess ammonia in the body. The late onset form of the condition tends to start later in life as there is some level of activity by the defective enzyme. The condition tends to be less severe and can be triggered by a change in diet, illness or some other stress on the body.

Argininosuccinase lyase deficiency, neonatal: A rare inherited urea cycle disorder caused by lack of enzymes (argininosuccinase lyase) needed to turn ammonia into urea resulting in excess ammonia in the body. The neonatal form of the condition can result in death or severe complications if not treated early enough.

Argininosuccinic aciduria: A rare inherited disorder of the urea cycle characterized by the lack of an enzyme (argininosuccinate lyase) which is needed to remove nitrogen from the body so a lack of the enzyme leads to a build-up of ammonia in the blood.

Aromatase deficiency: A congenital deficiency of the enzyme called aromatase which is needed to convert androgens to estrogens.

Aromatic amino acid decarboxylase deficiency: A rare inborn error of metabolism involving the deficiency of an enzyme (aromatic L-amino acid decarboxylase) needed to process aromatic amino acids. This results in a deficiency of neurotransmitters such as dopamine and serotonin. The condition manifests as movement and neurological problems.

Aspartylglucosaminidase deficiency: A rare glycoprotein metabolism disorder caused by a deficiency of an enzyme called aspartylglucosaminidase. Patients tend to develop normally during the first few years of life and development continues slowly until adolescence when mental retardation becomes progressively worse.

Aspartylglucosaminuria: A rare glycoprotein metabolism disorder caused by a deficiency of an enzyme called aspartylglucosaminidase. Patients tend to develop normally during the first few years of life and development continues slowly until adolescence when mental retardation becomes progressively worse.

Aspartylglycosaminuria: A rare glycoprotein metabolism disorder caused by a deficiency of an enzyme called aspartylglucosaminidase. Patients tend to develop normally during the first few years of life and development continues slowly until adolescence when mental retardation becomes progressively worse.

Atransferrinemia: A rare inherited condition characterized by the absence of a compound called transferring which results in a buildup of iron in the body's tissues as well as anemia.

Attenuated congenital adrenal hyperplasia: A late onset form of congenital adrenal hyperplasia where insufficient adrenal corticosteroids are produced by the body due to the deficiency of a particular chemical. The severity of symptoms varies from person to person and onset may occur as early as childhood.

Baker-Winegrad disease: A very rare syndrome caused by a deficiency of the enzyme fructose-1-6-diphosphatase which impairs the body's ability to break down fructose that is consumed in the diet.

Bantu siderosis: An iron overload disorder initially observed in South African people. The disorder involves abnormal iron deposits in the liver. It is believed that some African people are predisposed to an increased ability to absorb iron.

Bartter's syndrome, antenatal type 1: A rare genetic kidney disorder that causes hypokalemia. A defect in the NKCC2 gene impairs the functioning of the Na-Cl cotransporter and leads to electrolyte imbalance. The rate of death is high prior to diagnosis.

Bartter's syndrome, type 3: A rare condition characterized by an electrolyte imbalance caused by mutations of the chloride channel gene (ClCNKb). It differs from Bartter's syndrome type I and type II in the absence of nephrocalcinosis. The severity of the condition is greatly variable.

Berardinelli-Seip congenital lipodystrophy, type 1: A rare genetic disorder characterized by early-onset diabetes mellitus, loss of body fat, serious insulin resistance, high blood triglycerides and fatty liver. Type 1 is distinguished from type 2 by the origin of the genetic defect. Type 1 is caused by a defect on the AGPAT2 gene on chromosome 9q34.3. Type 1 seems to be less severe with some cases of type 2 resulting in premature death which can occur as early as the first year of life. Type 2 also involves mental retardation which is not seen in type 1.

Berardinelli-Seip congenital lipodystrophy, type 2: A rare genetic disorder characterized by early-onset diabetes mellitus, loss of body fat, serious insulin resistance, high blood triglycerides and fatty liver. Type 2 is distinguished from type 2 by the origin of the genetic defect. Type 2 is caused by a defect on the BSCL2 gene on chromosome 11q13. Type 2 seems to be more severe with some cases resulting in premature death which can occur as early as the first year of life. Type 2 also involves mental retardation which is not seen in type 1.

Beta ketothiolase deficiency: A rare inherited disease characterized by the bodies inability to metabolise certain amino acids and products of the breakdown of fat. Harmful levels of organic acids build up in the body and cause ketoacidic attacks.

Beta-mannosidosis: A very rare type of inherited glycoprotein storage disease where deficiency of an enzyme called beta-mannosidase results in a build-up of certain sugars (oligosaccharides) which can harm the body.

Beta-ureidopropionase deficiency: A metabolic disorder where the deficiency of an enzyme (Beta-ureidopropionase) results mainly in neurological abnormalities such as mental retardation. The symptoms are variable however.

Bielschowsky disease: An eye disorder where one eye tends to drift upwards while the other remains fixed.

Bile acid synthesis defect, congenital, 2: A defect which prevents the body from making bile acid which results in progressive liver disease. The defect is a deficiency of a particular enzyme (cholestasis with delta(4)-3-oxosteroid 5-beta-reductase) needed to make bile acid.

Bile acid synthesis defects, congenital, 1: A defect which prevents the body from making bile acid which results in progressive liver disease. The defect is a deficiency of a particular enzyme (3-beta-hydroxy-delta-5-C27-steroid oxidoreductase) needed to make bile acid.

Bile acid synthesis defects, congenital, 2: A defect which prevents the body from making bile acid which results in progressive liver disease. The defect is a deficiency of a particular enzyme (cholestasis with delta(4)-3-oxosteroid 5-beta-reductase) needed to make bile acid.

Bile acid synthesis defects, congenital, 3: A defect which prevents the body from making bile acid which results in progressive liver disease. The defect involved a deficiency of 7-alpha-hydroxylase which is an enzyme needed to prevent the accumulation of 27-hydroxycholesterol which is toxic to the liver.

Biotinidase deficiency: A metabolic disorder where the body lacks the enzyme biotinidase needed to process the vitamin called biotin (vitamin H) into carboxylase enzymes.

Biotinidase deficiency, late onset: A metabolic disorder where the body lacks the enzyme biotinidase needed to process the vitamin called biotin (vitamin H) into carboxylase enzymes. The severity of symptoms may vary depending on the degree of deficiency. Severe cases can result in metabolic acidosis which can lead to death if treatment isn't given.

Boyd-Stearns syndrome: A rare syndrome associated with various metabolic disorders such as glycosuria, acidosis, albuminuria and hypochloremia. Symptoms include rickets during infancy, short stature, low blood phosphate levels, malnutrition and osteoporosis.

Broad beta disease: An inherited condition involving a defect in the transport of lipids which causes the development of lipid deposits (xanthomas) under the skin in certain parts of the body.

Butyrylcholinesterase deficiency: A metabolic disorder involving an enzyme (butyrylcholinesterase) deficiency. It results in prolonged recovery from the effects of certain anesthetics such as succinylcholine and mivacurium which are muscle relaxants. The severity of the deficiency will determine the length of time taken to recover from anesthetic. In severe cases, patients can take more than 8 hours to recover.

C1esterase deficiency: C1esterase deficiency is a condition characterized by swelling under the skin or mucosal tissue - the skin, respiratory tract or gastrointestinal tract may be affected. The condition may be inherited or acquired. Symptoms tend to develop over a few days and then abate after two to five days. Swelling attacks may occur fairly regularly e.g. weekly or sporadically e.g. once or twice a year.

CDG syndrome (generic term): Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. The main symptom in all the disorders is psychomotor retardation but other variable symptoms also occur depending on the subtype of the disorder.

CDG syndrome type 3: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 3 has variable symptoms.

CDG syndrome type 4: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 4 is caused by a genetic defect which involves the gene for a particular enzyme (dolichyl-P-mannose:Man-5-GlcNAc-2-PP-dolichyl-mannosyltransferase).

CDG syndrome type I: A rare genetic disorder where the body is unable to synthesize glycoproteins which results in multisystem problems.

CDG syndrome type Ic: A very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 1C has a differs from the other subtypes by the type of enzyme which is deficient.

Carbamoyl-phosphate synthase 1 deficiency: A very rare inherited urea cycle disorder where the lack of the enzyme carbamoyl phosphate synthetase prevents ammonia from being turned into urea and being excreted in the urine. Excess ammonia builds up in the body which can cause serious complications or even death if left untreated.

Carbohydrate deficiency glycoprotein syndrome type II: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 2 is caused by a genetic defect which involves the gene for a particular enzyme (Golgi localized N-acetyl-glucosaminyltransferase II). Type 2 tends to have more severe psychomotor retardation than type 1 but there is no peripheral neuropathy or underdeveloped cerebellum.

Carnitine Palmitoyl Transferase II Deficiency: A very rare inherited deficiency of a particular enzyme (Carnitine palmitoyl transferase 1) prevents fatty acids being transported to the part of the cell that converts it to energy. There are two main subtypes of the disorder with each involving a slightly different form of the enzyme. Type I can be readily managed through diet. Type II has three subtypes: the myopathic form affects mainly the muscles; the hepatocardiomuscular form affects the liver and heart muscle; and the lethal neonatal form affects muscles and organs and usually results in death during the first year of life.

Carnitine palmitoyl transferase 1 deficiency: A very rare inherited deficiency of a particular enzyme (Carnitine palmitoyl transferase I) prevents fatty acids being transported to the part of the cell that converts it to energy.

Carnitine palmitoyl transferase 2 deficiency: A very rare inherited deficiency of a particular enzyme (Carnitine palmitoyl transferase) which prevents fatty acids being transported to the part of the cell that converts it to energy. There are two main subtypes of the disorder with each involving a slightly different form of the enzyme. Type I can be readily managed through diet. Type II has three subtypes: the myopathic form affects mainly the muscles; the hepatocardiomuscular form affects the liver and heart muscle; and the lethal neonatal form affects muscles and organs and usually results in death during the first year of life.

Carnitine palmitoyl transferase II deficiency, myopathic: A very rare metabolic disorder where deficiency of a particular enzyme (CPT II) prevents muscle fats being converted to energy. Prolonged exercise can cause an episode of muscle symptoms. The myopathic form of the condition is the least severe and tends to affect only the muscles.

Carnitine palmitoyl transferase deficiency: A very rare inherited deficiency of a particular enzyme (Carnitine palmitoyl transferase) which prevents fatty acids being transported to the part of the cell that converts it to energy. There are two main subtypes of the disorder with each involving a slightly different form of the enzyme. Type I can be readily managed through diet. Type II has three subtypes: the myopathic form affects mainly the muscles; the hepatocardiomuscular form affects the liver and heart muscle; and the lethal neonatal form affects muscles and organs and usually results in death during the first year of life.

Carnitine transporter deficiency: An inherited deficiency of carnitine caused by the impaired ability of the carnitine transporter protein to carry the carnitine to where it is needed. Instead the carnitine is excreted through the urine. Fasting or illness can trigger a severe attack.

Carnitine-acylcarnitine translocase deficiency: A very rare inherited metabolic disorder where long-chain fatty acids can't be metabolized properly because the compound needed to transport it is faulty. Ultimately this prevents certain fats (long-chain acylcarnitine) being converted to energy and results in a build up of the fat which is harmful to body organs and tissues.

Carnosinase deficiency: A very rare inherited metabolic disorder characterized by severe neurological abnormalities such as mental retardation and myoclonic seizures.

Caspase-8 deficiency: A rare type of immunodeficiency disorder caused by a deficiency of caspase-8. Caspase-8 an important part of the immune system as it is involved in the activation of T lymphocytes, B lymphocytes and natural killer cells.

Ceroid lipofuscinosis, neuronal: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). The 10 different type of the disorder are distinguished by the origin of the genetic defect.

Ceroid lipofuscinosis, neuronal 10: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 10 involves a deficiency of cathepsin D and involves an initial period of normal development with neurodegenerative symptoms starting during the early school years.

Ceroid lipofuscinosis, neuronal 3, Juvenile: A progressive genetic disorder where defective lipid metabolism that causes blindness, neurological deterioration, dementia leading to total incapication within years and death within 10-15 years.

Ceroid lipofuscinosis, neuronal 5: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 5 is distinguished from other types by the origin of the genetic defect.

Ceroid lipofuscinosis, neuronal 6, late infantile: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 6 usually occurs between the ages of 2 to 6 years. Type 6 is distinguished from other types by the origin of the genetic defect.

Ceroid lipofuscinosis, neuronal 7: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 7 is distinguished from other types by the origin of the genetic defect.

Ceroid lipofuscinosis, neuronal 8: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 8 is distinguished from other types by the origin of the genetic defect.

Ceroid lipofuscinosis, neuronal 8, northern epilepsy variant: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 8, northern epilepsy variant is distinguished from other types by the origin of the genetic defect. Mental retardation tended to occur by middle age despite normal development during the first few years of life.

Ceroid lipofuscinosis, neuronal 9: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 9 is distinguished from other types by the origin of the genetic defect.

Ceroid storage disease: A rare metabolic storage disease characterized by the abnormal deposits of a waxy substance called ceroid lipfuscin in various parts of the body such as the liver, spleen and intestinal lining.

Cholesteryl ester transfer protein deficiency: A rare inherited disorder of cholesterol regulation where a deficiency of a transport molecule (cholesteryl ester transfer protein) results in cholesterol level abnormalities. The transport protein moves cholesterol from HDL molecules to other lipoproteins and hence regulates the size of HDL particles and plasma levels of HDL cholesterol. There is disagreement as to whether the condition increases, decreases or has no effect on the risk of coronary heart disease.

Chondrocalcinosis: A rare inherited metabolic disorder where the chemical calcium pyrophosphate dihyrdate is deposited in one or more joints in the body - usually the knee is affected.

Chondrodysplasia punctata with steroid sulfatase deficiency: A genetic skeletal and skin disorder involving a deficiency of steroid sulfatase. The skin condition is characterized by large brownish scales which can occur almost anywhere on the skin and can be disfiguring. The face, scalp, palms and soles are usually not involved. The skeletal disorder involves abnormal bone calcification near the joints also results in shortened limbs.

Citrulline transport defect: A rare metabolic disorder where citrulline is unable to be transported within the body which affects growth. In one case, a 19 year old had the height and weight of a 6 year old.

Citrullinemia: Citrullinemia is an inherited urea cycle disorder which causes toxic substances including ammonia to build up in the blood. There are two main subtypes of Citrullinemia (I and II) which are caused by different genetic abnormalities and result in different symptoms. Milder forms may present in childhood and rare late-onset forms (adult-onset) may not cause symptoms until adulthood.

Citrullinemia I: A very rare urea cycle disorder where a lack of the enzyme argininosuccinate synthetase prevents ammonia being turned into urea which can then be excreted in the urine. The build up of ammonia in the body can cause harmful effects. The neonatal form of citrullinemia type I is generally more serious than the later onset form which may sometimes be mild enough to produce no symptoms.

Citrullinemia I, later-onset: A very rare urea cycle disorder where a lack of the enzyme argininosuccinate synthetase prevents ammonia being turned into urea which can then be excreted in the urine. The build up of ammonia in the body can cause harmful effects. The later-onset form of citrullinemia type I is generally milder than the neonatal form and may sometimes be mild enough to produce no symptoms.

Citrullinemia II: A very rare urea cycle disorder involving a deficiency of the transport compound called Citrin. Citrin transports aspartate to where the enzyme argininosuccinic acid synthase can combine it with citrulline to make argininosuccinic acid. The deficiency prevents ammonia being turned into urea which can then be excreted in the urine. The build up of ammonia in the body can cause harmful effects.

Cobalamin R Binder Protein Deficiency: A rare inherited condition where the lack of a protein (R binder protein) results in a deficiency of cobalamin (vitamin B12). The condition is considered benign and no treatment is needed.

Coenzyme Q cytochrome c reductase deficiency of: A rare genetic defect where an enzyme deficiency (CoQ-Cytochrome C reductase) disrupts cellular processes. Any of a variety of the components of the enzyme may be missing or defective and hence the clinical presentation and severity may vary. The deficiency may result in a variety of symptoms and conditions of variable severity such as cardiomyopathy, fatal infant conditions and Leber's myopathy.

Complex 1 mitochondrial respiratory chain deficiency: A rare genetic defect where an enzyme deficiency (NADH CoQ) disrupts cellular processes and causes various organic acid disorders. Any of a variety of the components of the enzyme may be missing or defective and hence the clinical presentation and severity may vary. Presentation may range from infantile death to various disorders such as Leigh's disease, Parkinson's disease and cardiomyopathy.

Complex 4 mitochondrial respiratory chain deficiency: A very rare inherited metabolic disorder where the body doesn't have enough of an enzyme called enzyme cytochrome C oxidase (COX or Complex IV) which is needed in the process of energy production by body cells. There are two subtypes: the benign infantile type only affects muscles whereas the fatal infant type affects the hearty and kidneys as well as the muscles.

Complex 5 mitochondrial respiratory chain deficiency: A rare genetic defect where an enzyme deficiency (ATP synthetase) disrupts cellular processes. Any of a variety of the components of the enzyme may be missing or defective and hence the clinical presentation and severity may vary. The deficiency may result in a variety of symptoms and conditions of variable severity such as Leber's myopathy, Leigh syndrome, cardiomyopathy and NARP (neuropathy, ataxia, retinitis pigmentosa).

Congenital Disorder of Glycosylation, Type 1n: A very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 1N has a defect in the RFT1 gene which results in decreased activity of an enzyme called dolichol-phosphage-mannose (Dol-P-M).

Congenital Disorder of Glycosylation, Type 1o: A very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 1O has a defect in the DPM3 gene which results in decreased activity of an enzyme called dolichol-phosphage-mannose (Dol-P-M).

Congenital Disorders of Glycosylation: Congenital disorders of glycosylation is a group of disorders involving abnormally synthesis of N-linked oligosaccharides. There is a long chain of events involved in the synthesis and defects may occur with any of the compounds or enzymes involved in the process. Progressive impairment and regression of skills often occurs after a period of normal development following birth.

Congenital adrenal hyperplasia -- non-classical form: A late onset form of congenital adrenal hyperplasia where insufficient adrenal corticosteroids are produced by the body due to the deficiency of a particular chemical. The severity of symptoms varies from person to person and onset may occur as early as childhood.

Congenital adrenal hyperplasia due to 17-alpha-hydroxylase deficiency: A rare genetic condition involving deficiency of 17-alpha-hydroxylase which impairs androgen production by the testes and estrogen production by the ovaries. This results in lack of development of secondary sexual characteristics and hypertension as well as other anomalies.

Congenital analbuminemia: A rare disorder where low or absent blood albumin levels are present at birth or soon after. Some cases are virtually asymptomatic as the liver compensates by making other proteins but other cases can result in symptoms such as osteoporosis and high blood lipid levels.

Congenital brain dysgenesis due to glutamine synthetase deficiency: A rare genetic metabolic disorder characterized by a deficiency of the glutamine synthase enzyme. This results in a lack of glutamine in the serum, urine and brain and spinal fluid. The condition results in severe brain malformations and infant death within weeks of birth.

Congenital disorder of Glycosylation type Ic: A very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 1C has a differs from the other subtypes by the type of enzyme which is deficient.

Congenital disorder of glycosylation type 1/IIX: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type I/IIX refers to cases where the specific abnormality cannot be determined.

Congenital disorder of glycosylation type 1F: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type IF is caused by a defect on chromosome 17p13.1-p12 and involves a defect on the MPDU1 gene.

Congenital disorder of glycosylation type 1G: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type IG is caused by a defect on chromosome 22q13.33 and involves the gene for a particular enzyme (dolichyl-P-mannose:Man-7-GlcNAc-2-PP-dolichyl-alpha-6-mannosyltransferase).

Congenital disorder of glycosylation type 1H: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Ih is caused by a defect on chromosome 11pter-p15.5 and involves the gene for a particular enzyme (dolichyl-P-glucose:Glc-1-Man-9-GlcNAc-2-PP-dolichyl-alpha-3-glucosyltransferase).

Congenital disorder of glycosylation type 1I: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Ii is caused by a defect on chromosome 9q22 and involves a defect on the ALG2 gene.

Congenital disorder of glycosylation type 1J: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Ij is caused by a defect on chromosome 11q23.3 and involves a defect on the gene for UDP-GlcNAc:dolichyl-phosphate N-acetylglucosamine phosphotransferase.

Congenital disorder of glycosylation type 1K: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Ik is caused by a defect on chromosome 16p13.3 and involves a defect in the gene for beta-1,4-mannosyltransferase. The disorder is generally fatal within a year or two of birth.

Congenital disorder of glycosylation type 1L: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Il is caused by a defect on chromosome 11q23 and involves a defect in the ALG9 gene.

Congenital disorder of glycosylation type 1M: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Im is caused by a defect on chromosome 9q34.11 and involves a defect in the TMEM15 gene.

Congenital disorder of glycosylation type 1X: Congenital disorder of glycosylation is a rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 1X also involves thrombocytopenia with normal levels of phosphomannomutase and phosphomannose isomerase. This form of the condition is severe and results in death during infancy.

Congenital disorder of glycosylation type 2C: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 2c is caused by a defect on chromosome 11p11.2 and involves a defect in the gene for GDP-fucose transporter.

Congenital disorder of glycosylation type 2D: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 2d is caused by a defect on chromosome 9p13 and involves a defect in the gene for beta-1,4-galactosyltransferase.

Congenital disorder of glycosylation type 2E: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 2e is caused by a defect on chromosome 16p and involves a defect in the gene for oligomeric complex-7.

Congenital disorder of glycosylation type 2F: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type IIf is caused by a defect on chromosome 6q25.16q15 and involves a defect on the gene for CMP-sialic acid transporter.

Congenital disorder of glycosylation type 2G: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type IIg is caused by a defect on chromosome 17q25.1 and involves a defect on the COG1 gene.

Congenital disorder of glycosylation type 2H: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type IIh is caused by a defect on chromosome 16q22.1 and involves a defect on the COG8 gene.

Congenital disorder of glycosylation type IIH: Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type IIh is caused by a defect on chromosome 16q22.1 and involves a defect on the COG8 gene.

Congenital disorder of glycosylation type X -- Bombay blood group phenotype: A rare inherited disorder characterized by abnormal neutrophil functioning which reduces the body's immunity. The abnormal neutrophils are unable to be transported to sites of infection due to their inability to adhere to certain blood vessel components which would normally lead them to the infection site. Infections may be life-threatening as the body is unable to destroy bacteria effectively. Type 2 LAD is where neutrophils can't adhere to necessary blood vessel components due to the absence of proteins on the blood vessel walls needed to bind and guide the neutrophils to the infection site.

Congenital hepatic porphyria: A rare congenital disorder where there is an excess of porphyrin (pigments) in the body. The liver is responsible for making porpyrins.

Congenital lactase deficiency: A congenital metabolic disorder where a deficiency of an enzyme called lactase impairs the body's ability to digest milk and other products that contain lactose. Symptoms tend to occur soon after consuming such products. The severity of symptoms depends on the degree of lactase deficiency.

Cormier Rustin Munnich syndrome: Deficiency of certain chemicals involved in the respiratory chain can result in various malformation depending on the chemical involved and the degree of deficiency.

Corticosterone Methyloxidase type I Deficiency: A very rare genetic disorder where deficiency of a particularly chemical (aldosterone synthase) results in a deficiency of aldosterone. The condition can be severe enough to cause infant death unless the patient is diagnosed and treated.

Cortisone reductase deficiency: An inborn error of steroid metabolism due to a deficiency of an enzyme called cortisone reductase (11-beta-hydroxysteroid dehydrogenase). This enzyme is needed to convert cortisone to cortisol.

Creatine deficiency, X-linked: A rare inherited disorder characterized mainly by mental retardation, seizures, short stature and facial anomalies. The disorder is caused by the absence of a compound needed to transport creatine and thus creatine levels may be normal or high, but the body is unable to utilize it.

Crigler-Najjar Syndrome: An autosomal recessive form of nonhemolytic jaundice due to the absence of the hepatic enzyme glucuronide transferase.

Crigler-Najjar syndrome, type 1: A rare congenital condition involving a total absence of the liver enzyme called glucoronyl transferase which is needed to change bilirubin into a form that can be removed from the body. The bilirubin builds up in the body and causes damage and severe symptoms.

Crigler-Najjar syndrome, type 2: A rare congenital condition involving a partial absence of the liver enzyme called glucoronyl transferase which is needed to change bilirubin into a form that can be removed from the body. The bilirubin builds up in the body and causes damage and symptoms but to a lesser extent than in type 1.

Cystinuria: A rare inherited condition characterized by the abnormal transport of various amino acids (cystine, lysine, arginine, ornithine) resulting in excess amounts in the urinary system where it can form stones.

Cytochrome C Oxidase Deficiency: Cytochrome C oxidase deficiency is a rare inherited condition involving insufficient quantities of the cytochromc C oxidase enzyme. This enzyme plays a role in the functioning of the energy producing part of body cells (mitochondria) and its deficiency impairs the energy-producing functions of the cells. The type and severity of symptoms can vary considerably depending on which particular cells in the body are affected and the degree of the enzyme deficiency. In some cases only skeletal muscles are affected whereas in other cases organs such as the heart and brain are involved. In other cases, the whole body may be involved.

Defect in synthesis of adenosylcobalamin: A rare genetic disorder characterized by the impaired ability to make a chemical called adenosylcobalamin. Adenosylcobalamin is a derivative of vitamin B12. The defect results a biochemical abnormality which affects the body's normal biochemical functioning.

Deficiency of Member 8 Acyl-CoA Dehydrogenace Family: An extremely rare metabolic disorder where the body is unable to metabolize certain proteins properly. More specifically, an insufficient level of the enzyme (isobutyryl-coenzyme A dehydrogenase) needed to metabolize the amino acid valine. The onset and severity of symptoms is variable.

Dehydratase deficiency: A very rare condition involving a deficiency of the enzyme called dehydratase. It is usually asymptomatic and often associated with high blood phenylalanine levels.

Dementia, familial British: A rare, early-onset inherited form of dementia caused by deposits of amyoid substances (amyloid) and degenerative nerve changes in the brain.

Developmental delay due to 2-methylbutyryl-CoA dehydrogenase deficiency: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.

Di Mauro-Hartlage syndrome: A rare inherited glycogen storage disorder involving a total absence of muscle phosphorylase needed to convert glycogen to glucose in the muscles. It is a rare, atypical variant of McArdle disease which causes death within months of birth.

Dibasic aminoaciduria 2: A rare condition where protein intolerance occurs as a result of a defect in the transport of dibasic amino acids through the intestines and kidneys. The amino acids (component of protein) can't be broken down properly and used by the body so it builds up and causes damage.

Dicarboxylicaminoaciduria: A rare metabolic syndrome involving a defect in the transport of certain amino acids (glutamate, aspartate) and resulting in high levels of dicarboxylic amino acids in the urine. Often no observable symptoms occur.

Dihydropyrimidine dehydrogenase deficiency: A metabolic error where a deficiency of an enzyme called dihydropyrimidine dehydrogenase prevents the normal metabolism of certain proteins. High levels of certain proteins are excreted in the urine. The enzyme is also needed the breakdown a chemotherapy drug called 5-flurouracil and its absence can result in a severe toxicity reaction.

Dobriner syndrome: An inherited metabolic disorder involving a deficiency of coproporphyrinogen oxidase. The condition is similar to but milder than intermittent porphyria and sometimes includes photosensitivity.

Dopamine beta-hydroxylase deficiency: A very rare disorder involving a deficiency of dopamine beta-hydroxylase which affects production of noradrenaline and adrenaline and results in symptoms such as low blood pressure on standing, droopy eyelids and stuffy nose.

Dunnigan syndrome: A rare metabolic disorder involving abnormal fat distribution where fat accumulates on areas such as the face, shoulders, neck and genitals but gradually disappears from the limbs, trunk and buttocks.

Eccentrochondrodysplasia: A rare inherited biochemical disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans) in various body tissues due to insufficient amounts of certain enzymes needed to break it down.

Electron Transfer Flavoprotein, deficiency of: A metabolic disorder involving an enzyme deficiency - electron transfer flavoprotein ubiquinone oxydoreductase. The severity of symptoms depends on the level of deficiency. The infant onset form is the most severe.

Encephalopathy due to GLUT1 deficiency: A rare inherited metabolic disorder where a genetic mutation results in the deficiency of an enzyme called glutaryl-CoA dehydrogenase which is required to metabolise certain amino acids (lysine, hydroxylysine and tryptophan). Problems occur when these metabolites build up in the body and cause neurological problems. Symptoms often develop following an acute infection or fasting. The severity of the condition is highly variable from development of neurological symptoms during infancy to asymptomatic adults. The degree of enzyme deficiency will usually determine the severity.

Familial HDL deficiency: A rare genetic disorder characterized by a deficiency of high density lipoproteins (HDL). Severity of symptoms is determined by the degree of deficiency. The disorder tends to run in families (familial).

Familial Hypercholesterolemia: A genetic abnormality which causes patients to have abnormally high cholesterol levels (low-density lipoproteins). The condition usually leads to early cardiovascular disease.

Familial Lactase Deficiency: A congenital metabolic disorder where normal amounts of lactase are produced but the lactase is defective and unable to digest milk and other products that contain lactose. Symptoms tend to occur soon after consuming such products.

Familial dysalbuminemic hyperthyroxinemia: An inherited characteristic involving increased levels of thyroxine in the blood and abnormal serum blood despite normal thyroid gland functioning. The condition may be mistaken for hyperthyroidism.

Familial hyperlipoproteinemia: A group of genetic disorder characterized by abnormal breakdown of lipoproteins which causes abnormal lipoprotein and lipid levels in the blood. There are various types of this condition: hyperlipoproteinemia type I, II, III, IV and V. The type and severity of symptoms vary between types. The disorder tends to run in families (familial).

Familial hyperlipoproteinemia type 1: A genetic disorder characterized by abnormal lipid (chylomicrons and high triglyceride lipids) breakdown which results in its accumulation in the blood. The disorder is caused by the reduced or absent activity of the enzyme lipoprotein lipase. The severity of the condition is determined by the degree of the deficiency and treatment. The disorder tends to run in families (familial).

Familial hyperlipoproteinemia type 3: A genetic disorder characterized by abnormal lipid (cholesterol and triglyceride) breakdown which causes it to accumulate in the blood. The disorder tends to run in families (familial).

Familial hypertryptophanemia: A rare genetic metabolic disorder characterized by high levels of tryptophan in the blood. The disorder tends to run in families (familial).

Familial infantile metachromatic leukodystrophy -- late infantile: An infantile form of an inherited biochemical disorder involving a deficiency of an enzyme called cerebroside sulfatase. The enzyme deficiency causes cerebroside sulfate to build up within the body and causes damage to the nervous system including the brain. The late infantile form of this disease is much more common than the juvenile or adult form.

Fanconi-Bickel syndrome: A rare inherited disorder where the impaired metabolism of carbohydrates results in a build-up of glycogen in the liver.

Farber Disease: A lysosomal storage disease due to defective ceramidase and characterized by hoarsness, aphonia , dermatitis and psychomotor retardation.

Farber's disease: A rare inherited biochemical disorder involving the deficiency of an enzyme called ceramidase resulting in the harmful accumulation of certain chemicals in the body which causes damage and inflammation.

Finnish lethal neonatal metabolic syndrome: A very rare lethal metabolic disorder characterized by a deficiency of complex III which causes brain, kidney and liver problems and ultimately results in early death.

Forbes disease: A rare inherited glycogen storage disease caused by a deficiency of the enzyme amylo-1,6-glucosidase resulting in a build up of glycogen in the liver and muscles.

Free sialic Acid storage disease: A rare inherited biochemical disorder characterized by the accumulation of sialic acid in the tissues and excretion of sialic acid in the urine. There are mild and severe forms of the condition - the severe form result in death before birth or within a few years of birth.

Fructosuria: A rare harmless asymptomatic condition caused by a lack of the liver enzyme called fructokinase which is needed to turn fructose into glycogen.

Fucosidosis: A rare progressive biochemical disorder involving deficiency of an enzyme (alpha-fucosidase) which results in accumulation of certain chemicals (glycosphingolipids) in the central nervous system and other body tissues.

Fucosidosis type 1: A rare biochemical disorder involving deficiency of an enzyme (alpha-fucosidase) which results in accumulation of certain chemicals (glycosphingolipids) in the central nervous system and other body tissues. It is an infantile form of fucosidosis which starts early and rapidly progresses to early death.

Fucosidosis type II: A form of the biochemical disorder called fucosidosis where an enzyme deficiency (alpha-fucosidase) results in the accumulation of certain chemicals (glycosphingolipids) in the central nervous system and other body tissues. Symptoms start later and progress slower than in type I and is distinguished by warty skin growths.

Fumaric aciduria: A rare inborn metabolic error where a deficiency of the enzyme fumarase due to a genetic defect impairs the body's ability to break down fumarate into malate which results in increased fumaric acid levels in the urine.

GM1 gangliosidosis: A rare biochemical disorder involving a deficiency of an enzyme (beta-galactosidase A) which results in the accumulation of harmful chemicals (GM1 gangliosides) in the central nervous system and other body tissues. Type 1 is a severe infantile form of the disorder and involves a greater degree of accumulation than type II or III.

GSD IIB -- formerly: A rare inherited disorder characterized by severe heart problems, varying degrees of muscle weakness and often mental retardation. Other symptoms such as mental retardation may also occur. The genetic anomaly manifests as a deficiency of a protein called LAMP-2 (Lysosomal-Associated Membrane Protein 2) which affects lysosomes. The condition is now known as Danon disease.

GSD2B -- formerly: A rare inherited disorder characterized by severe heart problems, varying degrees of muscle weakness and often mental retardation. Other symptoms such as mental retardation may also occur. The genetic anomaly manifests as a deficiency of a protein called LAMP-2 (Lysosomal-Associated Membrane Protein 2) which affects lysosomes. The condition is now known as Danon disease.

GTP cyclohydrolase deficiency: A rare metabolic disorder caused by an enzyme deficiency (GTP cyclohydrolase) which causes a harmful build up of phenylalanine in the blood.

Galactokinase deficiency: A rare condition where an enzyme deficiency (galactokinase) impaires the body's ability to break down galactose consumed in the diet.

Galactosemia: Any of a number of recessive disorders that cause accumulation of galactose in the blood from an inability to metabolise galactose

Galactosemia I: A rare inherited disorder where deficiency of a particular enzyme (galactose-1-phosphate uridyl transferase) prevents the metabolism of galactose which is a sugar component of milk. Ranges from milk intolerance in mild cases to death in severe untreated cases.

Galactosemia III: A rare inherited disorder where deficiency of a particular enzyme (UDP-Galactose-4-epimerase) prevents the metabolism of galactose which is a sugar component of milk. The condition may vary from mild to severe.

Gamma-cystathionase deficiency: A rare metabolic defect where a buildup of cystathionine in the body is due to an enzyme deficiency (cystathionine gamma-lyase) which normally converts methionine into cysteine. The condition is usually asymptomatic.

Gangliosidosis GM1 type 3: A rare biochemical disorder involving a deficiency of an enzyme (beta-galactosidase A) which results in the accumulation of harmful chemicals (GM1 gangliosides) in the central nervous system and other body tissues. Type III involves a lesser degree of accumulation than type II or I.

Gangliosidosis generalized GM1, type 1: A rare biochemical disorder involving a deficiency of an enzyme (beta-galactosidase A) which results in the accumulation of harmful chemicals (GM1 gangliosides) in the central nervous system and other body tissues. Type 1 is a severe infantile form of the disorder and involves a greater degree of accumulation than type II or III.

Gangliosidosis, generalized GM1 type 2: A rare biochemical disorder involving a deficiency of an enzyme (beta-galactosidase 1) which results in the accumulation of harmful chemicals (GM1 gangliosides) in the central nervous system and other body tissues. Type III involves a lesser degree of accumulation than type II or I. Death can occur early in life in severe cases but milder cases can survive into late childhood.

Gangliosidosis, generalized GM1 type 3: A rare biochemical disorder involving a deficiency of an enzyme (beta-galactosidase A) which results in the accumulation of harmful chemicals (GM1 gangliosides) in the central nervous system and other body tissues. Type III involves a lesser degree of accumulation than type II or I.

Gaucher Disease: A rare inherited biochemical disorder characterized by the deficiency of the enzyme called glucocerebrosidase and accumulation of glycosylceramide (glucocerebroside). There are three forms of this disease: type 1, 2 and 3.

Gaucher disease -- perinatal lethal form: A rare syndrome characterized by the association of abnormally tight skin and Gaucher disease which is a lipid storage disease. This is the most severe form of Gaucher disease.

Gaucher disease type 1: A rare inherited biochemical disorder characterized by the deficiency of the enzyme called glucocerebrosidase and accumulation of glycosylceramide (glucocerebroside). There are three forms of this disease: type 1, 2 and 3. Type 1 is the visceral, chronic form which usually starts during adulthood.

Gaucher disease type 2: A rare inherited biochemical disorder characterized by the deficiency of the enzyme called glucocerebrosidase and accumulation of glycosylceramide (glucocerebroside). There are three forms of this disease: type 1, 2 and 3. Type 2 is acute neurological form apparent in infancy.

Gaucher disease type 3: A rare inherited biochemical disorder characterized by the deficiency of the enzyme called glucocerebrosidase and accumulation of glycosylceramide (glucocerebroside). There are three forms of this disease: type 1, 2 and 3. Type 3 is a subacute neurological form which often first appears in childhood.

Glucocorticoid resistance: A rare condition where all or parts of the body are unable to respond to glucocorticoids. Symptoms depend on the level or resistance.

Glucose-6-Phosphate Dehydrogenase Deficiency: A rare enzyme abnormality involving a deficiency of the glucose-6-phosphate dehydrogenase which causes premature destruction of red blood cells. The excessive destruction of red blood cells can be triggered by certain infections or drugs or by eating fava beans.

Glucose-galactose malabsorption: An inherited metabolic disorder where the small intestine is unable to absorb and transport glucose and galactose that is consumed in the diet due to a lack of intestinal monosaccharidase.

Glutamate decarboxylase deficiency: A rare disorder of amino acid metabolism characterized by a deficiency of the enzyme called glutamate decarboxylase which causes seizures that will only respond to pyridoxine (vitamin B6).

Glutamate-cysteine ligase deficiency: A very rare condition characterized by an enzyme deficiency which leads primarily to hemolytic anemia which is usually quite mild. Care must be taken to avoid medications which can lead to a hemolytic crisis.

Glutamine deficiency, congenital: A rare genetic metabolic disorder characterized by a deficiency of the glutamine synthase enzyme. This results in a lack of glutamine in the serum, urine and brain and spinal fluid. The condition results in infant death within weeks of birth.

Glutaric Acidemia Type I: A condition which results in an inability to process the amino acids lysine, hydroxylysine and tryptophan

Glutaric Acidemia Type II: A condition which is characterized by an inability of the body to use fats and proteins of the body for energy

Glutaric aciduria 1: A rare inherited metabolic disorder where a genetic mutation results in the deficiency of an enzyme called glutaryl-CoA dehydrogenase which is required to metabolise certain amino acids (lysine, hydroxylysine and tryptophan). Problems occur when these metabolites build up in the body and cause neurological problems. Symptoms often develop following an acute infection or fasting. The severity of the condition is highly variable from development of neurological symptoms during infancy to asymptomatic adults. The degree of enzyme deficiency will usually determine the severity.

Glutaric aciduria 2: A metabolic disorder involving an enzyme deficiency - electron transfer flavoprotein ubiquinone oxydoreductase. The severity of symptoms depends on the level of deficiency. The infant onset form is the most severe and often results in death. Severe cases usually develop during childhood or infancy and usually involve metabolic acidosis and its associated symptoms. Milder cases may simply present with muscle weakness initially that develops in adulthood. Some cases may involve additional symptoms such as heart, liver and kidney problems, facial anomalies and genital abnormalities.

Glutaricaciduria 2B: A milder, later-onset form of glutaricaciduria where there is excessive blood and urine levels of glutaric acid due to the body's impaired ability to metabolize protein and fat into energy.

Glutaricaciduria type 1: A rare inherited metabolic disorder where a genetic mutation results in the deficiency of an enzyme called glutaryl-CoA dehydrogenase which is required to metabolise certain amino acids (lysine, hydroxylysine and tryptophan). Problems occur when these metabolites build up in the body and cause neurological problems. Symptoms often develop following an acute infection or fasting. The severity of the condition is highly variable from development of neurological symptoms during infancy to asymptomatic adults. The degree of enzyme deficiency will usually determine the severity.

Glutaricaciduria type 3: A very rare inherited metabolic disorder involving a deficiency of the glutaryl-CoA oxidase enzyme. The disorder is severe with death occurring during infancy or soon after birth.

Glutaryl-CoA dehydrogenase deficiency: A rare inherited metabolic disorder where a genetic mutation results in the deficiency of an enzyme called glutaryl-CoA dehydrogenase which is required to metabolise certain amino acids (lysine, hydroxylysine and tryptophan). Problems occur when these metabolites build up in the body and cause neurological problems. Symptoms often develop following an acute infection or fasting. The severity of the condition is highly variable from development of neurological symptoms during infancy to asymptomatic adults. The degree of enzyme deficiency will usually determine the severity.

Glutathione Synthetase Deficiency: An inborn error of metabolism where insufficient glutathione is produced. Glutathione is an antioxidant which helps destroy unstable molecules that can cause damage to cells and helps develop certain cell components. The condition is due to insufficient glutathione synthetase enzyme. The condition may range from mild, resulting in excessive destruction of red blood cells, to severe which includes neurological symptoms.

Glutathione synthetase deficiency, intermediate: An inborn error of metabolism where insufficient glutathione is produced. Glutathione is an antioxidant which helps destroy unstable molecules that can cause damage to cells and helps develop certain cell components. The condition is due to insufficient glutathione synthetase enzyme. The condition may range from mild, resulting in excessive destruction of red blood cells, to severe which includes neurological symptoms.

Glutathione synthetase deficiency, mild: An inborn error of metabolism where insufficient glutathione is produced. Glutathione is an antioxidant which helps destroy unstable molecules that can cause damage to cells and helps develop certain cell components. The condition is due to insufficient glutathione synthetase enzyme. The condition may range from mild, resulting in excessive destruction of red blood cells, to severe which includes neurological symptoms.

Glutathione synthetase deficiency, severe: An inborn error of metabolism where insufficient glutathione is produced. Glutathione is an antioxidant which helps destroy unstable molecules that can cause damage to cells and helps develop certain cell components. The condition is due to insufficient glutathione synthetase enzyme. The condition may range from mild, resulting in excessive destruction of red blood cells, to severe which includes neurological symptoms.

Glutathionuria: A very rare inborn error of metabolism where insufficient gamma-glutamyl transpepidase causes excess glutathione levels in the body.

Glyceraldehyde-3-phosphate dehydrogenase deficiency: A rare genetic syndrome characterized by a deficiency of an enzyme (Glyceraldehyde-3-phosphate dehydrogenase) which is involved in breaking down carbohydrates consumed in the diet in order to produce energy.

Glycine encephalopathy, atypical mild form: A rare disorder of amino acid metabolism where glycine are unable to be metabolized properly due to defects in the glycine cleavage system. The atypical mild form tends to be quite mild and can be difficult to diagnose due to the nonspecific symptoms.

Glycine encephalopathy, classical neonatal early-onset form: A rare disorder of amino acid metabolism where glycine are unable to be metabolized properly due to defects in the glycine cleavage system. The early onset classical neonatal form usually starts after a period of normal development during the first 6 months of life.

Glycine synthase deficiency: A rare genetic disorder characterized by high blood glycine levels which is toxic to the body. The severity of the condition varies according to the degree of deficiency and age of onset. The classical neonatal form is generally quite severe, the atypical mild form which generally includes symptoms such as aggressiveness, behavioral problems and speech problems. The transient neonatal form involves high blood glycine levels at birth which then returns to normal within a couple of months - there was no neurological or developmental impairment.

Glycine synthase deficiency, type 1: A rare genetic disorder characterized by high blood glycine levels. It is caused by a defect in the P protein (pyridoxal phosphate-dependent glycine decarboxylase) in the energy creating center of cells (mitochondria).

Glycine synthase deficiency, type 2: A rare genetic disorder characterized by high blood glycine levels. It is caused by a defect in the T protein (tetrahydrofolate-requiring enzyme) in the energy creating center of cells (mitochondria).

Glycogen Storage Disease IIb -- formerly: A rare inherited disorder characterized by severe heart problems, varying degrees of muscle weakness and often mental retardation. Other symptoms such as mental retardation may also occur. The genetic anomaly manifests as a deficiency of a protein called LAMP-2 (Lysosomal-Associated Membrane Protein 2) which affects lysosomes. The condition is now known as Danon disease.

Glycogen Storage Disease IXa1: Glycogen storage disease type IX is a relatively mild glycogen storage disease which involves a deficiency of the enzyme hepatic phosphorylase kinase. Thee are four subtypes of the condition, each caused by a different genetic defect which results in the enzyme deficiency. Type IXa is linked to a defect in the PHKA2 gene on chromosome Xp22.2-p22.1. It is inherited in a X-linked recessive manner which means that only males will exhibit symptoms though females may be carriers.

Glycogen Storage Disease IXb: Glycogen storage disease type IX is a relatively mild glycogen storage disease which involves a deficiency of the enzyme hepatic phosphorylase kinase. There are four subtypes of the condition, each caused by a different genetic defect which results in the enzyme deficiency. Type IXb is linked to a defect in the PHKG2 gene on chromosome 16q12-q13 and is inherited in a recessive manner. The metabolic anomaly results in the accumulation of glycogen in the liver and muscle.

Glycogen Storage Disease IXc: Glycogen storage disease type IX is a relatively mild glycogen storage disease which involves a deficiency of the enzyme hepatic phosphorylase kinase. There are four subtypes of the condition, each caused by a different genetic defect which results in the enzyme deficiency. Type IXc is linked to a defect in the PHKG2 gene on chromosome 16p12.1-p11.2 and is inherited in a recessive manner.

Glycogen Storage Disease Type I: An inherited metabolic disorder where a deficiency of the enzyme glucose-6-phosphatase prevents glycogen being turned into glucose leading to a buildup of glycogen in the liver and kidneys. Most problems tend to develop during adulthood.

Glycogen Storage Disease XIV: A rare genetic disorder where the deficiency of a chemical called phosphoglucomutase-1 results in problems with glycogen storage within the body. The main symptoms tend to revolve around muscle problems.

Glycogen branching deficiency: A rare metabolic disorder where an enzyme deficiency (glycogen branching enzyme) results in a harmful buildup of glycogen byproducts in the liver, muscle and even the heart in some cases. The severity of symptoms is variable depending on the degree of enzyme deficiency and how strictly treatment measures are adhered to.

Glycogen debranching deficiency: A rare metabolic disorder where an enzyme deficiency (amylo-1,6-glucosidase) results in a harmful buildup of glycogen byproducts in the liver, muscle and even the heart in some cases. The severity of symptoms is variable depending on the degree of enzyme deficiency and how strictly treatment measures are adhered to.

Glycogen storage disease type 1C: A genetic metabolic disorder involving a deficiency of the enzyme glucose-6-phosphatase (due to a defect in the microsomal phosphate) which results in the accumulation of glycogen in various tissues. G6P is stored as glycogen until the body needs to convert it to a sugar for energy. The enzyme deficiency prevents the conversion and hence low blood sugar levels result.

Glycogen storage disease type 1D: A genetic metabolic disorder involving a deficiency of the enzyme glucose-6-phosphatase (due to a defect in the microsomal glucose transporter) which results in the accumulation of glycogen in various tissues. G6P is stored as glycogen until the body needs to convert it to a sugar for energy. The enzyme deficiency prevents the conversion and hence low blood sugar levels result.

Glycogen storage disease type 2: A rare inherited biochemical disorder involving the harmful accumulation of certain chemicals (glycogen) in body tissues due to the deficiency of an enzyme (?-glucosidase or acid maltase) needed to break it down.

Glycogen storage disease type 2B: A rare inherited biochemical disorder involving the harmful accumulation of certain chemicals (glycogen) in body tissues due to the deficiency of an enzyme (?-glucosidase or acid maltase) needed to break it down. Type IIB usually starts during childhood.

Glycogen storage disease type 2B -- formerly: A rare inherited disorder characterized by severe heart problems, varying degrees of muscle weakness and often mental retardation. Other symptoms such as mental retardation may also occur. The genetic anomaly manifests as a deficiency of a protein called LAMP-2 (Lysosomal-Associated Membrane Protein 2) which affects lysosomes. The condition is now known as Danon disease.

Glycogen storage disease type 6: A rare, generally mild form of inherited glycogen storage disease where a deficiency of phosphorylase b kinase leads to hypoglycemia and accumulation of glycogen in the liver.

Glycogen storage disease type 7: An inherited metabolic disorder where there is a deficiency of phosphofructokinase-1 in the muscle and a partial deficiency in red blood cells which prevents glucose being converted to energy during exercise.

Glycogenosis type 2: A rare inherited biochemical disorder involving the harmful accumulation of certain chemicals (glycogen) in body tissues due to the deficiency of an enzyme (?-glucosidase or acid maltase) needed to break it down. The severity of the condition is variable and onset may occur during infancy, childhood or adulthood.

Glycogenosis type 8: A mild glycogen storage disease which affects males only and involves a deficiency of the enzyme phosphorylase b-kinase.

Glycogenosis, type 0: A rare metabolic disorder caused by a genetic deficiency of a liver enzyme called glycogen synthase.

Glycogenosis, type O: A rare metabolic disorder caused by a genetic deficiency of a liver enzyme called glycogen synthase.

Goldberg syndrome: A rare lysosomal storage disorder characterized by an enzyme deficiency (neuraminidase and beta-galactosidase) which results in a build-up of glycoproteins in the urine. There are three main subtypes: infantile, juvenile and adult forms. The early infantile form is the most severe and often results in death during infancy.

Grange syndrome: A rare syndrome characterized by the abnormal narrowing of various arteries, high blood pressure, heart defects, fragile bones and short, webbed digits. The congenital heart defects are not present in all cases.

Grasbeck-Imerslund Disease: A rare inherited disorder characterized by vitamin B12 deficiency which results from the body's inability to absorb vitamin B12 from the foods eaten.

Guanidinoacetate methyltransferase deficiency: A rare disorder of amino acid metabolism where glycine and proline are unable to be metabolized properly due to deficiency of the enzyme called guanidinoacetate methyltransferase.

HADH deficiency: A rare inherited form of biochemical disorder characterized by the deficiency of a particular enzyme (3-Hydroxyacyl-CoA Dehydrogenase). The enzyme deficiency only affects certain body tissues, in particular the skeletal muscles. The lack of enzyme activity prevents some fats being converted into energy. Symptoms tend to be exacerbated during fasting as during fasting, the body tries to rely more heavily on fats for energy. Fatty acids that are not completely metabolized due to the enzyme deficiency may build up in various organs and cause serious complications.

HMG CoA synthetase deficiency: An inherited metabolic defect due to the deficiency of an enzyme (HMG CoA synthetase) needed to form ketone bodies. Symptoms are often preceded by periods of fasting or illness.

HMG-CoA lyase deficiency: A rare inherited metabolic disorder where deficiency of a particular enzyme impairs the processing of amino acids in food to create energy and causes various symptoms. Stresses on the body such as infection, fasting and heavy exercise can trigger an episode.

Hemochromatosis type 1: A genetic disorder where too much iron is absorbed from food and it is stored in various parts of the body which can cause damage. Type 1 is the most common form of the disorder, has an adult onset and is inherited recessively.

Hemochromatosis type 2: A rare genetic disorder where too much iron is absorbed from food and it is stored in various parts of the body which can cause damage. Type 2 is a more severe type, has a juvenile onset and is inherited recessively.

Hemochromatosis type 3: A rare genetic disorder where too much iron is absorbed from food and it is stored in various parts of the body which can cause damage. Type 3 has an onset that is between type 1 and type 2 and is inherited recessively.

Hemochromatosis type 4: A rare genetic disorder where too much iron is absorbed from food and it is stored in various parts of the body which can cause damage. Type 4 has an adult onset but is inherited dominantly.

Hemolytic anaemia due to adenylate kinase deficiency: A rare condition characterized by the association of a deficiency of an enzyme called adenylate kinase and hemolytic anemia. There appears to be no conclusive cause-effect relationship between the two characteristics as some patients with virtually no pyruvate kinase activity can have only mild or no anemia whereas others with significant pyruvate kinase activity can have anemia.

Hemolytic anemia due to adenylate kinase deficiency: A rare condition characterized by the association of a deficiency of an enzyme called adenylate kinase and hemolytic anemia. There appears to be no conclusive cause-effect relationship between the two characteristics as some patients with virtually no pyruvate kinase activity can have only mild or no anemia whereas others with significant pyruvate kinase activity can have anemia.

Hepatorenal tyrosinemia: A rare genetic metabolic disorder characterized by a deficiency of particular enzymes which prevents the breakdown of tyrosine which then builds up in the liver. Type 1 involves a deficiency of the enzyme fumaril acetoacetate hydrolase.

Hereditary Hemochromatosis: A genetic disorder where too much iron is absorbed from food and it is stored in various parts of the body which can cause damage. There are 4 types of hemochromatosis and they are distinguished by age of onset, genetic cause and type of inheritance. Some sufferers may be asymptomatic.

Hereditary carnitine deficiency: An inherited deficiency of carnitine resulting primarily in muscle problems. Severe symptoms can be triggered by periods of illness or fasting.

Hereditary hyperuricemia: High levels of uric acid in the blood due to an inherited metabolic disorder which disrupts the normal metabolic processes involving purine consumed in the diet.

Hereditary non-spherocytic hemolytic anemia: A group of genetic blood disorders where red blood cells are prematurely destroyed resulting in anemia if they are not replaced fast enough. The blood cells are destroyed because they have abnormally weak membranes which gives them an irregular shape rather than normal doughnut shape.

Hereditary primary Fanconi disease: A rare inherited disorder characterized by defective reabsorption of various substances such as phosphate, potassium, amino acids and glucose which manifests as a wide range of abnormalities and problems.

Heterozygous Familial Hypercholesterolemia: Heterozygous Familial Hypercholesterolemia is an inherited condition involving abnormal lipid metabolism. Cholesterol levels tend to be with coronary artery disease usually developing before the age of 50. The heterozygous form of the condition is not as severe as the homozygous form of the disease.

Histidinemia: A metabolic disorder where there is a deficiency of the histidase enzyme which is needed to metabolise the amino acid called histidine. Histidine levels then buildup of histidine in the blood and urine.

Homocarnosinosis: A very rare metabolic disorder where a deficiency of homocarnosinase causes a harmful buildup of homcarnosine. Symptoms include mental retardation, retinal pigmentation and spastic diplegia.

Homocystinuria: A rare inherited metabolic disorder involving the amino acid methionine and resulting in a harmful accumulation of homocysteine in the body.

Homocystinuria due to cystathionine beta-synthase deficiency: A rare genetic biochemical disorder where a deficiency of cystathionine beta-synthase results in high levels of methionine and homocysteine in the blood and reduced levels of cyteine in the blood. There are two subtypes of the disorder with varying manifestations. One type responds to Vitmain B6 supplementation and the other doesn't. Those who do respond to Vitamin B6 tend to have milder manifestations.

Homocystinuria due to defect in methylation (cbl g): An inherited organic acid disorder where an enzyme deficiency (methionine synthase) impairs the body's ability to break down certain proteins consumed in the diet. This results in a buildup of methylmalonic acid and homocystine which results in harmful affects. It is a form of vitamin B12 deficiency.

Homocystinuria due to defect in methylation cbl e: An inherited organic acid disorder where an enzyme deficiency (methionine synthase reductase) impairs the body's ability to break down certain proteins consumed in the diet. This results in a buildup of methylmalonic acid and homocystine which results in harmful affects. It is a form of vitamin B12 deficiency.

Homozygous Familial Hypercholesterolemia: Homozygous Familial Hypercholesterolemia is a severe inherited condition involving abnormal lipid metabolism. Cholesterol levels tend to be very high with problems occurring early in life. Death from a heart attack can occur within the first few years of life in severe cases.

Hydroxyacyl-coa dehydrogenase, type 2, deficiency: A rare genetic disorder involving the deficiency of an enzyme (hydroxyacyl-coa dehydrogenase). The severity of the symptoms is highly variable with some cases resulting in death during the first decade while others suffer psychomotor and regression. Some cases simply involve developmental delay.

Hyperglycerolemia: A genetic condition where an enzyme deficiency (glycerol kinase) results in an accumulation of glycerol in the body as well as it's excretion through the urine.

Hyperglycerolemia, adult form: A genetic condition where an enzyme deficiency (glycerol kinase) results in an accumulation of glycerol in the body as well as it's excretion through the urine. The adult form of the condition usually causes no noticeable symptoms.

Hyperglycerolemia, infantile form: A genetic condition where an enzyme deficiency (glycerol kinase) results in an accumulation of glycerol in the body as well as it's excretion through the urine. The infantile form of the condition involves a deficiency of complex glycerol kinase and is associated with a variety of physical and developmental abnormalities.

Hyperglycerolemia, juvenile form: A genetic condition where an enzyme deficiency (glycerol kinase) results in an accumulation of glycerol in the body as well as it's excretion through the urine. The juvenile form of the condition occurs in chidren and can cause serious complications.

Hyperhomocysteinemia: Excessive homocysteine levels in blood. It is often associated with folate or cobalamin deficiency as well as genetic defects. Severity of symptoms is determined by how high the homocysteine levels are. Sufferers are generally asymptomatic until the onset of premature arterial disease later in life. Other symptoms such as mental retardation only occur in severe cases where the homocysteine levels are extremely high.

Hyperimidodipeptiduria: A very rare genetic disorder characterized by an excessive level of imidodipeptides in the urine due to a deficiency of the enzyme prolidase.

Hyperinsulinism due to glucokinase deficiency: An inherited condition characterized by high insulin levels due to deficiency of glucokinase. The lack of glucokinase prevents the pancreas from detecting low blood sugar so insulin continues to be secreted which keeps the blood sugar level low. Severe symptoms such as seizures and coma can result if sugar levels drop too low.

Hyperinsulinism due to glutamodehydrogenase deficiency: An inherited condition characterized by high insulin and ammonia levels in the blood due to an enzyme deficiency (glutamate dehydrogenase). Episodes of low blood sugar can be triggered by fasting for too long or eating a protein meal. Severe symptoms such as seizures and coma can result if sugar levels drop too low.

Hyperlipoproteinemia type 3: A rare genetic disorder characterized by the body's impaired ability to break down certain lipids (triglycerides) which results in their buildup in the blood.

Hyperlysinemia, persistent: A rare genetic disorder where the body lacks enzymes (lysine ketoglutarate reductase and saccharopine dehydrogenase) to metabolize lysine which then causes a harmful builds up of lysine in the blood and urine and saccharopins in the urine. Some patients are asymptomatic while others have severe symptoms.

Hyperornithinemia: Excessive levels of ornithine in the blood caused by a deficiency of mitochondrial ornithine aminotransferase.

Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome: A very rare inherited metabolic disorder where ammonia builds up in the body due to a defect in the transport of ornithine which prevents ammonia being converted to urea and being excreted through the urine. The severity of the condition is variable.

Hyperphenylalaninemia with primapterinuria: A rare disorder characterized by high blood phenylalanine levels and excretion of primapterine in the urine due to an enzyme deficiency (pterin-4-alpha-carbinolamine dehydratase). The condition usually produces no clinical symptoms.

Hyperpipecolatemia: A rare metabolic disorder characterized by high blood levels of pipecolic acid.

Hyperprolinaemia type I: Hyperprolinemia is a very rare inherited metabolic disorder involving high levels of proline in the blood and urine due to a deficiency of the enzyme proline oxidase. There are two subtypes of the disorder with type II being more severe (higher blood levels of praline). Type I is generally asymptomatic whereas type II tends to involve neurological symptoms.

Hyperprolinemia type I: Hyperprolinemia is a very rare inherited metabolic disorder involving high levels of proline in the blood and urine due to a deficiency of the enzyme proline oxidase. There are two subtypes of the disorder with type II being more severe (higher blood levels of praline). Type I is generally asymptomatic whereas type II tends to involve neurological symptoms.

Hyperprolinemia type II: A very rare inherited metabolic disorder involving high levels of proline in the urine due to a deficiency of the enzyme delta-pyrrolidine 5-carboxylate acid dehydrogenase. Blood proline levels are higher than for hyperprolinemia type I.

Hyperreninemic Hypoaldosteronism, Familial 2: A very rare genetic disorder where deficiency of a particularly chemical results in a deficiency of aldosterone. The condition can be severe enough to cause infant death unless the patient is diagnosed and treated.

Hypertryptophanemia: A rare genetic metabolic disorder characterized by high levels of tryptophan in the blood.

Hypobetalipoproteinemia, familial: An genetic lipid metabolism disorder characterized by low betalipoprotein levels in blood. The disorder tends to run in families (familial). The severity of the condition is determined by whether the genetic defect is inherited from one or both parents.

Hypocalciuric hypercalcemia, familial: An inherited benign disorder of calcium metabolism which results in high blood calcium levels and low urine calcium levels. The condition is generally asymptomatic and the abnormality is discovered accidentally during blood tests.

Hypocalciuric hypercalcemia, familial, type 3: Familial hypocalciuric hypercalcemia is an inherited benign disorder of calcium metabolism which results in high blood calcium levels and low urine calcium levels. The condition is generally asymptomatic and the abnormality is discovered incidentally during blood tests. Subtype 31 involves a genetic defect on chromosome 19q13. Bone strength problems may occur in some patients in the later stages of life.

Hypophosphatemia, Familial: An inherited disorder involving low blood phosphate levels due to problems with the transport of phosphate and problems with vitamin D metabolism. Vitamin D and phosphates are not properly absorbed from the kidneys which can lead to bone problems if not treated.

Hypothyroidism due to iodide transport defect: Low thyroid hormone levels in infants due to abnormal iodide transport in the body caused by a genetic defect. The severity of the condition varies depending on the extent of the defect and the length of time taken to diagnose the condition. Symptoms tend to become worse, the longer the condition is undiagnosed.

I cell disease: A rare inherited biochemical disorder characterized by the harmful accumulation of chemicals (glycoproteins and glycoplipids) due to the deficiency of an enzyme (UDP-N-acetylglucosamine-I-phosphotransferase).

Inborn amino acid metabolism disorder: A group of inherited disorders where the body is not able to metabolize amino acids consumed in the diet. Amino acids are a part of carbohydrates, fats and proteins and are metabolized in order to provide energy or to make other needed compounds. There are many steps involved in metabolism and the severity can be greatly variable depending on the exact nature of the disorder.

Inborn branched chain aminoaciduria: Any inherited disorder that results in abnormally high levels of branched chain amino acids in the urine. Branched chain amino acids includes leucine, valine and isoleucine. Maple syrup urine disease is the main inborn disorder that causes this form of aminoaciduria.

Inborn urea cycle disorder: A genetic disorder involving a deficiency of one of the enzymes needed in the urea cycle. The urea cycle is the process of removing ammonia from blood stream by converting it to urea and excreting it via urine. A build-up of ammonia in the blood is toxic to the body and can cause serious brain damage. The progressively severe symptoms usually become obvious within the first few weeks of birth. Nevertheless, mild or partial enzyme deficiencies may cause little or no symptoms or symptoms that don't start until later in life.

Infantile hypophosphatasia: An inherited bone disorder due to an inborn error of metabolism characterized by a deficiency of alkaline phosphate. The condition becomes noticeably during infancy and involves a period of normal development (about 6 months) followed by deterioration due to bone demineralization.

Infantile sialic acid storage disorder: A rare inherited biochemical disorder characterized by the accumulation of sialic acid in the tissues and excretion of sialic acid in the urine. The disorder results in death within the first few years of life - usually in infancy.

Intermediate cystinosis: Cystinosis is a condition where excess amino acid cystine builds up to harmful levels in the body. The intermediate form of cystinosis starts later than the nephropathic form but the symptoms are the same.

Intrinsic factor, congenital deficiency of: A very rare disorder where a deficiency of a protein called intrinsic factor prevents vitamin B12 from being absorbed from the stomach. Thus, vitamin B12 deficiency occurs which leads to anemia.

Isobutyric aciduria: An extremely rare metabolic disorder where the body is unable to metabolize certain proteins properly. More specifically, an insufficient level of the enzyme (isobutyryl-coenzyme A dehydrogenase) needed to metabolize the amino acid valine. The onset and severity of symptoms is variable.

Isobutyryl-coenzyme A dehydrogenase deficiency: An extremely rare genetic condition where the body is unable to metabolize certain proteins properly. More specifically, an insufficient level of the enzyme (isobutyryl-coenzyme A dehydrogenase) needed to metabolize the amino acid valine.

Isovaleric Acidemia: A condition which is characterized by a defect in the pathway of leucine catabolism

Kanzaki disease: A very rare inherited metabolic disorder where deficiency of an enzyme (alpha-N-acetylgalactosaminidase) causes glycoplids to accumulate in body tissues and result in various symptoms. Type 2 occurs during the second or third decade of life and is milder than type I and doesn't involve neurological degeneration.

Krabbe disease, atypical, due to saposin A deficiency: An inherited biochemical disorder which results in neurological regression within a few months of birth. Death usually occurs during the first few years of life. The disorder is similar to Krabbe disease but is differentiated by the genetic origin of the biochemical defect. Krabbe disease involves a defect in the galactocerebrosidase gene whereas atypical Krabbe disease involves a defect in the prosaposin gene which causes a deficiency of saposin A.

Krabbe leukodystrophy: A rare inherited biochemical disorder involving the deficiency of an enzyme called galactocerebrosidase. It is a leukodystrophy which refers to a group of genetic disorders that affect the growth of the protective coating around the brain nerves.

L-3-alpha-hydroxyacyl-CoA dehydrogenase, short chain, deficiency: A rare inherited form of biochemical disorder characterized by the deficiency of a particular enzyme (3-Hydroxyacyl-CoA Dehydrogenase). The enzyme deficiency only affects certain body tissues, in particular the skeletal muscles. The lack of enzyme activity prevents some fats being converted into energy. Symptoms tend to be exacerbated during fasting as during fasting, the body tries to rely more heavily on fats for energy. Fatty acids that are not completely metabolized due to the enzyme deficiency may build up in various organs and cause serious complications.

LADHSC deficiency: A rare inherited form of biochemical disorder characterized by the deficiency of a particular enzyme (3-Hydroxyacyl-CoA Dehydrogenase). The enzyme deficiency only affects certain body tissues, in particular the skeletal muscles. The lack of enzyme activity prevents some fats being converted into energy. Symptoms tend to be exacerbated during fasting as during fasting, the body tries to rely more heavily on fats for energy. Fatty acids that are not completely metabolized due to the enzyme deficiency may build up in various organs and cause serious complications.

Laron Dwarfism: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron Pituitary Dwarfism: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron Syndrome: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron Type Pituitary Dwarfism 1: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron syndrome type 1: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron syndrome type 2: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron-type Dwarfism Phenotypic Syndrome: Laron syndrome is a rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results. Type 1 involves a defect in the growth hormone receptor gene which prevents the hormone from binding and being used. Hence there are high levels of free growth hormone in the plasma. Type II involves a problem with the processing of the growth hormone once it has been bound properly to the cell surface.

Laron-type dwarfism: A rare genetic disease where the body has sufficient growth hormones but lacks receptors to utilize the hormone and hence dwarfism results.

Lathosterolosis: A very rare disorder where an enzyme (sterol C5-desaturase) deficiency prevents the normal synthesis of cholesterol in the body. The deficiency causes various malformations, mental retardation and liver disease.

Lecithin-cholesterol acyltransferase deficiency, LCAT: A rare genetic disorder characterized by an enzyme deficiency (lecithin:cholesterol acyltransferase) which impairs the breakdown of lipoproteins which then builds up and causes damage to tissues. The condition is characterized by corneal disorders, anemia, protein in the urine and ultimately, kidney failure. Partial deficiency of the enzyme (alpha-LCAT) results in a condition called Fish-Eye disease whereas deficiency of the whole enzyme (alpha- and beta-LCAT) causes a condition called Norum disease.

Lesch-Nyhan syndrome: Inherited biochemical disorder of purine metabolism caused by the virtual absence of an enzyme called hypoxanthine-guanine phosphoribosyltransferase or HPRT.

Leucinosis: A term used to describe high levels of leucine in the body. It is associated with a metabolic disorder called maple syrup urine disease where there is a deficiency of an enzyme needed to break down leucine so it builds up within the body.

Leukodystrophy, pseudometachromatic: Patients with pseudometachromatic leukodystrophy have a deficiency of the enzyme arylsulphatase but don't have any symptoms of the condition.

Lipoamide dehydrogenase deficiency: A very rare enzyme deficiency (dihydrolipoamide dehydrogenase) which can cause lactic acidosis. The age of onset and symptoms are variable.

Lipoid congenital adrenal hyperplasia: A rare form of congenital adrenal hyperplasia where the early phase of adrenal cortisol production is defective which causes mineralocorticoid deficiency. Male pseudohermaphroditism is the main characteristic of this disorder.

Lipoproteine lipase deficiency: A rare inherited inborn error of metabolism involving the absence of the enzyme called lipoprotein lipase which results in increased blood triglyeride and chylomicron levels.

Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency: A rare inherited genetic condition where the body is unable to convert certain fats to energy i.e. there is not enough of a certain enzyme (3-hydroxyacyl-coenzyme A dehydrogenase) which is needed to metabolize a type of fat called long-chain fatty acids. The build-up of these fatty acids in the body causes damage.

Lysosomal glycogen storage disease with normal acid maltase activity: A rare inherited disorder characterized by severe heart problems, varying degrees of muscle weakness and often mental retardation. Other symptoms such as mental retardation may also occur. The genetic anomaly manifests as a deficiency of a protein called LAMP-2 (Lysosomal-Associated Membrane Protein 2) which affects lysosomes.

M/SCHAD deficiency: A rare inherited form of biochemical disorder characterized by the deficiency of a particular enzyme (3-Hydroxyacyl-CoA Dehydrogenase). The enzyme deficiency only affects certain body tissues, in particular the skeletal muscles. The lack of enzyme activity prevents some fats being converted into energy. Symptoms tend to be exacerbated during fasting as during fasting, the body tries to rely more heavily on fats for energy. Fatty acids that are not completely metabolized due to the enzyme deficiency may build up in various organs and cause serious complications.

MPS 3 C: A rare inherited biochemical disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans) due to deficiency of an enzyme called acetyl-CoA:alpha-glucosamide N-acetyltransferase. Mucopolysaccharide levels build up and are then deposited in various tissues.

MPS 3 D: A rare inherited biochemical disorder characterized by the accumulation of mucopolysaccharides (glycosaminoglycans) due to deficiency of an enzyme called N-acetylglucosamine-6-sulfate sulfatase. Mucopolysaccharide levels build up and are then deposited in various tissues.

Male pseudohermaphroditism, incomplete hereditary (type 1): A rare condition involving a deficiency of dihydrotestosterone receptor which impairs the function of androgen receptors and hence the androgen (male hormone) is partially or completely ineffective depending on the level of deficiency. The degree of feminization ranges from feminine phenotype through to male phenotype depending on the level of androgen insensitivity.

Malonic aciduria: A very rare genetic disorder where a deficiency of a particular enzyme (malonyl-CoA decarboxylase) impairs the body's ability to convert fatty acids into energy that can be used by muscles such as the heart muscle. Fatty acids also accumulate in the body as they are not metabolized.

Mannosidosis, alpha B lysosomal: A rare inherited metabolic disorder involving a deficiency of an enzyme (alpha-mannosidosase) which results in the accumulation of certain chemicals in the body which leads to progressive damage.

Maple syrup urine disease: A very rare inherited metabolic disorder involving abnormal metabolism of branched chain amino acids (leucine, isoleucine and valine) and resulting in severe illness which generally leads to death if not treated. Other milder variants of the disease do exist and tend to occur as late as childhood. Even mild form can result in mental and physical retardation if untreated.

Maple syrup urine disease, type 1A: A very rare inherited metabolic disorder involving abnormal metabolism of branched chain amino acids (leucine, isoleucine and valine) and resulting in severe illness which generally leads to death if not treated. Even mild form can result in mental and physical retardation if untreated. Various types of maple syrup urine disease involve different genetic defects - type 1A specifically involves a defect in the E1-alpha subunit gene.

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